Double band type carrier

ABSTRACT

An improved type carrier for an impact printer of the rotating typewheel class includes a typewheel having first and second bands of type characters, each band of which is arranged in a helix about a spherical periphery of the typewheel. Each band lies in a plane, and the planes of the bands are set at a small acute angle to each other. The typewheel is secured to a spherical portion about which it is deflected in order to align a selected one of said bands with a print hammer in response to a control signal signifying that a desired character on the selected band is to be imprinted on a record medium.

United States Patent Hutley July 29, 1975 DOUBLE BAND TYPE CARRIER Primary ExaminerEdgar S. Burr P [75] Inventor. Ronald W F Hutley Lansdale a Assistant Exammer paul J. Hlrsch [73] Assignee: Sperry Rand Corporation, Blue Bell, Attorney, A o Firm Rene A. Kuypers [22] Filed: Dec. 21, 1973 57 ABSTRACT [21] Appl' 427586 An improved type carrier for an impact printer of the rotating typewheel class includes a typewheel having [52 US. Cl. 197/49; 101 /93.23; 197/18 first and second bands of y characters. each band [51] Int. Cl B41j 1/34 of which is arranged in a helix about a Spherical P [58] Field of Search 197/18, 49, 55; 101/9323 p y 9f the yp Each band lies in a plane, and the planes of the bands are set at a small acute 5 References Ci d angle to each other. The typewheel is secured to a UNITED STATES PATENTS spherical portion about which it is deflected in order to align a selected one of said bands with a print hamg ii mer in response to a control signal signifying that a de- 362533l 12/1971 i g 197/55 X sired character on the selected band is to be imprinted 3,630,335 12/1971 Chamness 197 49 a record medlum- 3,669,237 6/1972 Wagner et al. 197/18 X 5 Cl 3 D 3,674,126 7/1972 Decker et a1v 197/55 l INPUT CODE BAND A DECODER PATENTEB JUL 2 91975 DECODER BAND B DOUBLE BAND TYPE CARRIER BACKGROUND OF THE INVENTION The present invention is directed to an impact printer and more particularly relates to an improvement on an impact printer of the rotating typewheel class.

In the US. Pat. No. 2,843,243, issued July 15, 1958, Earl E. Masterson, inventor, there is described an impact printer which includes a rotating print member having a preferred form of a typewheel. In that patent, the typewheel includes a series of type characters arranged about the periphery of the typewheel in the form of a helical path. The axis of rotation of the wheel parallels a print line, and the typewheelis continuously rotated about its axis while at the same time being moved along the axis. The pitch of the helical path defined by the type characters is set so as to compensate for the movement of the wheel along its axis, and all the characters scan past a first columnar print position during one rotation of the wheel, and then scan past the second columnar print columnar position during a second revolution, and so on. This print mechanism has a number of advantages. For example, it is simple in design, and is relatively high in speed, so that printing takes place while the wheel is moving from column to column.

One manner in which the advantages in flexibility of such a printer can be extended is by either increasing the number of printable type characters without decreasing the printing rate, or by increasing the printing rate while using the same number of printable characters as in said prior art patent mentioned above. One of the problems associated with prior art devices, attempting to effect the above-mentioned improvements, has been that when the printing speed is increased while attempting to maintain the existing configurations and font sizes, the result has been a poorer print quality. Correspondingly, any increase in a font size while maintaining existing print speed with the existing configuration has also led to poorer print quality. It is a primary object of the present invention to provide an improved impact printer for either increasing the number of characters without decreasing the printing rate or to increase the printing rate while using an existing number of printable characters in a font.

Another object of the invention is to provide a typewheel and typewheel support arrangement for improving the ease and efficiency of deflecting and aligning multiple band typewheels.

SUMMARY OF THE INVENTION According to one salient feature of my invention, an improved impact printer for representing characters on a record medium includes a continuously rotating type carrier having two bands of type characters on a typewheel, said bands being arranged so that the respective planes of said bands are set at a small acute angle to each other, at least a portion of the type characters on one band being different in type than the type characters on the other band. In one form, the printer may include a shaft aligned across a row of a record medium; a hub keyed to said shaft and said typewheel, and having a spherical portion on which said typewheel is secured to prevent radial motion relative to said hub, said typewheel being deflectable about the axis of said hub. In a preferred form the face of the typewheel may be spherical with respect to the axis of rotation of the typewheel.

BRIEF DESCRIPTION OF THE DRAWINGS Other advantages and features of the present invention may be best shown by reference to the appended drawings, in which like reference numerals identify like components, and in which:

FIG. 1 is a diagrammatic showing of the printer mechanism of the invention when viewed from above;

FIG. 2 is a partial sectional view of the typewheel and support diagram in arrangement taken through the typewheel on a plane perpendicular to axis X;

FIG. 3 is a partial sectional view taken along a plane passing through axis X.

DETAILED DESCRIPTION OF THE INVENTION Reference is now made to FIG. I where there is shown a type carrier having a typewheel 10, disposed adjacent one side of a record rnedium 12, and aligned with a print hammer 16 which is disposed adjacent the other side of record medium 12. Hammer 16 is actuated by a control signal of a suitable signal level which may be applied to a print actuator solenoid 22 by way of the conductor 24. Hammer 16 and solenoid 22 are mounted on a movable carriage 18. Record medium 12 is advanced upwardly by the space of one line at the end of the printing of a line by conventional means (not shown herein). The typewheel 10, as will be seen hereinafter, is adapted to be continuously rotated about the axis line X while the typewheel l0 and the carriage 18 are translated across a row of record medium 12 in the direction indicated by the arrow 14, and print hammer 16 is actuated at a selective time at each columnar location along a row of the record medium to effect the imprinting of a desired type character (on typewheel 10) on record medium 12. For the sake of simplicity, the inking ribbon has been omitted in the drawing.

Typewheel 10 is coupled to and rotates continuously with a shaft or rod 26, which rod has threads 27. The pitch of the threads 27 is such that in response to a complete revolution of the typewheel 10, the typewheel 10 will move laterally a distance which is equal to the distance between two parallel planes that are perpendicular to the shaft 26, and respectively pass through the opposite ends of a complete band of characters. As a result, if the typewheel 10 starts its operation at the left end of the print station and moves continuously toward the right end thereof, each type character on typewheel 10 will pass each of a plurality of discrete spots on the record medium 12, and each discrete spot corresponds to a columnar position on the record medium where printing takes place. One mechanism for effecting such a translation may include means for moving the carriage 18 and for the rotation of typewheel 10, such as is shown in the aforementioned Earl E. Masterson US. Pat. No. 2,843,243, issued July 15, 1958 and assigned to the assignee of this invention, to which reference is herein made.

According to a salient feature of the invention, typewheel 10 may include a plurality of bands of type characters, such as first band 10A which lies in a plane defined by reference line 30, and second band 10B which lies in a plane defined by the reference line 32. Each band may, as in the above Masterson Patent, be arranged in a helix about the periphery of typewheel l0, and may be so arranged that the respective planes of the bands are set at a small acute angle to each other such as angle a. In more particular, it will be seen that the characters forming each of the bands 10A and 10B are arranged to lie in a helical path as described by the Masterson patent above and that the reference lines 30 and 32 represent the centerlines for the bands 10A and 10B, respectively. As is well known from the prior art the characters forming the helical print bands 10A and 10B shift from one side of the respective print band centerlines to the other as one progresses around the wheel. The pitch of the helix is related to the direction of the wheel 10 translation. For example, assume that the wheel 10 is being translated along the shaft 26 from left to right as indicated by arrow 14 and that the wheel is being rotated in a counterclockwise direction when viewed from the right-hand end of shaft 26. With these assumptions it will be seen that the characters comprising each of the bands 10A and 108 would be positioned to the right side of their respective centerlines at the start of each band and then gradually shift to the left side of their respective centerlines at the end of the bands. For the sake of simplicity, the bands have not been arranged in a helix in the accompanying drawings. Furthermore, the bands are arranged about the circumference of the print wheel so that the center lines 30 and 32 of the bands of characters intersect at two points, the first intersection point being identified by reference numeral 34, and the second being on the opposite side of typewheel 10, 180 away. In addition, the face 36 of typewheel 10 is spherical in shape with reference to the axis of rotation of the typewheel; i. e., the typewheel face is spherical in a direction generally perpendicular to the radii of typewheel 10.

Such an arrangement of type-bands on typewheel l permits different type characters to be apportioned between bands A and 10B. According to one arrangement, if there is desired to be an increase in the printing rate, bands 10A and 108 may share equally the total number of characters in a print font. Hence, band 10A may have one half of the font type characters, and band 10B may have the other half of the type font characters so that the diameter of the typewheel is reduced and printing speed is increased. If it is desired to increase the total number of characters that may be printed while printing at the same printing rate, then the characters may be apportioned between bands 10A and 108 so that a first band, say band 10A, may have more than half the number of type characters in the font, and the second band, band 10B, may have less than half the total number of characters in a font. This latter arrangement is depicted in FIG. 1. In the preferred form of the invention, neither band will have any type character which is present on the other band; i. e., the type characters on one band are different in type than any of the type characters on the other band. Of course, other arrangements may be desirable to meet special needs.

Also shown in FIG. I is a deflection means, including a forked lever 40, for deflecting typewheel 10 about a spherical portion 42 of the hub 44, in order to align a selected one of the bands 10A or 108 with print hammer 16. The forked lever 40 may have a pair of guide plates 46 and 48 which abut the respective sides of typewheel l0, and which are bored so that they surround hub 44. The plates 46 and 48, which travel on the hub 44 at the peripheral portions of spherical section 42, exert a force on typewheel 10 during deflection and cause typewheel 10 to deflect about the spherical section 42. Lever 40 is coupled at one end to the side portion 52 of a carriage 50 through a biasing spring 53. Lever 40 is also connected, through an actuating rod 54, to a solenoid 56 which is mounted on the side portion 58 of carriage 50. Solenoid 56 may receive a control signal over input conductor 60 from the printer logic circuitry. A control signal so applied at a suitable signal level is effective to actuate rod 54 to deflect lever 40 to the left and to thereby cause band 108 to be aligned with print hammer 16. In operation, the choice of a character band for printing the next character may be made just before the blank portion of the print wheel is adjacent the print hammer, so that the actual deflection of typewheel 10 takes place while the blank portion of the typewheel is opposite the hammer. This allows typewheel 10 to be positioned for printing the next character in the selected character band. It should be noted that the side portions 52 and 58 of carriage 50 are apertured so that they surround and freely ride along shaft 26 under a bearing force applied by hub 44, and that the upper portion 62 of carriage 50 slides along carriage bar 64 through an aperture formed in element 62 in carriage 50 as the typewheel 10 is translated across record medium 12.

Typewheel deflection may be effected in one of several ways. By way of example, the typewheel may be deflected from band 10A to band 10B, or correspondingly from band 10B to 10A. Also, typewheel 10 may be deflected from a midpoint position intermediate bands 10A and 10B, and after said deflection and printing, the typewheel may be returned to the midpoint home position after imprinting a desired character at a desired columnar location along record medium 12.

If, for example, the typewheel is deflected from one band to another, one method for implementing such deflection may consist of a band B decoder 90, as shown in FIG. 1, for decoding an input code of signals to determine if the character to be printed is a coded signal on band 108. If the input code represents a character on band 10B, then the band B decoder will set flip-flop 92 over conductor 94, and the high signal over the set output line 60 of the flip-flop 92 will energize solenoid 56 and thereby draw typewheel l0 counterclockwise over spherical portion 42 resulting in band 108 being aligned for printing. If the input code represents a character on band 10A, then the band A decoder 96 will reset flip-flop 92 over conductor 98 and the signal over the set output line 60 of flip-flop 92 will go low thereby de-energizing solenoid 56. When this occurs the spring 53 operating through fork 40 will draw typewheel 10 in a clockwise direction over spherical portion 42 resulting in band 10A being aligned for printing.

To summarize the foregoing, when print band 10A is active print wheel 10 will be deflected to the position shown in FIG. 1. When, however, print band 10B is active and therefore solenoid 56 energized, wheel 10 is tilted to the left as viewed in FIG. 1 to a position where the centerline 32 of band 108 occupies the position shown for centerline 30 in FIG. 1. In either position of the wheel 10, the circular path defined by the respective bands 10A and 10B is the same and the characters comprising the selected band scan across the print hammer 16 in a direction such as to compensate for the translational motion of the wheel 10.

Referring now to the sectional views of FIGS. 2 and 3, it can be seen that the hub 44 is keyed to shaft 26 by means of a plurality of ball bearings 66, 67 and 68, which ball bearings are trapped between hub 44 and shaft 26 along a slot 70 by means of a circumferential lock spring 72, in a manner in which the ball bearings allow freedom of movement for hub 44 on shaft 26, but do not allow any relative radial motion between hub 44 and shaft 26. The typewheel I0 is keyed to hub 42 by means of a plurality of keys (two of which are referenced at numerals 80 and 82 in FIG. 2). The keys, through keyways such as the keyways 74, 76, and 78 in FIG. 2, lock typewheel to hub base 84 so that no relative radial motion (about centerline X) is possible between the hub base 84, in both instances, and typewheel 10. I-Iub 44, which is rotationally driven through threads 27, drives the typewheel 10 through the keys 80, 82 etc. The typewheel 10 can of course be deflected about spherical portion 42.

Hence, typewheel 10 may be continuously rotated across a row of the medium 12 on shaft 26, while means is provided for deflecting typewheel 10 to align a selected one of the bands 10A and 10B with the print hammer 16 in response to a control signal over conductor 60 signifying that a desired type character on said selected band is to be imprinted on the record medium.

While a preferred embodiment of this invention has been described above, it is intended that the description and drawing are illustrative and not limiting and that all modifications, constructions and arrangements which fall within the scope and spirit of the present invention may be made.

I claim:

I. An impact printer for representing characters on a record medium, comprising: a continuously rotating typewheel having an axis of rotation and having a generally spherically shaped face section perpendicular to the radii of said typewheel, said typewheel having first and second bands of type characters, at least some of the type characters on said first band being different in type than the type characters on said second band, each band being arranged on the face of said typewheel in a circular path extending about the periphery of said typewheel, said circular path defining a type plane. said type planes intersecting each other at two points on the wheel and crossing a projection of the axis of the typewheel at a predetermined angle when its typeband is in printing position and at an angle other than said predetermined angle when its typeband is not in printing position; a hub keyed to said typewheel, said typewheel being deflectable about the axis of said hub, print actuator means aligned with said typewheel; means for translating said typewheel and said print actuator means across a row of said record medium, and means for deflecting said typewheel to align a selected one of said bands with said print actuator means in response to a control signal signifying that a desired character on said selected band is to be imprinted on said record medium.

2. The invention defined in claim I further comprising a shaft aligned across a row of said record medium, said hub being also keyed to said shaft.

3. The invention defined in claim 1 wherein said hub has a spherical portion on which said typewheel is secured to prevent radial motion relative to said hub.

bored to surround said hub. 

1. An impact printer for representing characters on a record medium, comprising: a continuously rotating typewheel having an axis of rotation and having a generally spherically shaped face section perpendicular to the radii of said typewheel, said typewheel having first and second bands of type characters, at least some of the type characters on said first band being different in type than the type characters on said second band, each band being arranged on the face of said typewheel in a circular path extending about the periphery of said typewheel, said circular path defining a type plane, said type planes intersecting each other at two points on the wheel and crossing a projection of the axis of the typewheel at a predetermined angle when its typeband is in printing position and at an angle other than said predetermined angle when its typeband is not in printing position; a hub keyed to said typewheel, said typewheel being deflectable about the axis of said hub, print actuator means aligned with said typewheel; means for translating said typewheel and said print actuator means across a row of said record medium, and means for deflecting said typewheel to align a selected one of said bands with said print actuator means in response to a control signal signifying that a desired character on said selected band is to be imprinted on said record medium.
 2. The invention defined in claim 1 further comprising a shaft aligned across a row of said record medium, said hub being also keyed to said shaft.
 3. The invention defined in claim 1 wherein said hub has a spherical portion on which said typewheel is secured to prevent radial motion relative to said hub.
 4. The invention defined in claim 3 wherein said means for deflecting said typewheel includes a forked lever for deflecting said typewheel about said spherical portion of said hub.
 5. The invention defined in claim 4 and further comprising first and second guide plates secured to said forked lever, said first and second guideplates being adjacent respective sides of said typewheel and being bored to surround said hub. 